amnesiac

As a noun amnesiac

is person who suffers from loss of memory (amnesia).

As an adjective undefined is

lacking a definition or value.

As nouns the difference between amnesic and amnesiac

is that amnesic is a person suffering from amnesia while amnesiac is person who suffers from loss of memory (amnesia).

As an adjective amnesic

is of, pertaining to, or suffering from amnesia.

As nouns the difference between amnesiac and amnesias

is that amnesiac is person who suffers from loss of memory (amnesia) while amnesias is .